With the progress of IT, the diversification of the usage, and other circumstances, there has been desired a substrate with a fine projection-and-recess pattern, such as a semiconductor device having a finer pattern formed therein. However, so-called photolithography techniques have the disadvantage of requiring an expensive stepper and photomask for forming a finer pattern, and therefore, the development of a novel production technique that can supersede the photolithography has been demanded.
In 1995, Professor Chou of University of Minnesota, et al. proposed a nanoimprint lithography technique as a technique to replicate a substrate with a fine projection-and-recess pattern at low cost.
Such nanoimprint lithography is a method in which, not by using a conventional photolithography technique, but by using an electron-beam lithography technique which is currently poor in productivity, a mold provided with projections and recessions ranging from several tens to several hundreds of nm in a surface thereof is pressed into contact with a thin thermoplastic resin film on a substrate to transfer a fine pattern to the film, and using the molded thin resin film as a resist mask or a deposition mask, a substrate with a fine projection-and-recess pattern is produced.
This method includes a thermal cycle step configured with heating, pressurization, maintenance, cooling, decompression, and mold-peeling, and is therefore called thermal nanoimprint lithography.
By contrast, there is a method called photo-nanoimprint lithography, in which, using a mold and a photocurable composition that is a low-viscosity liquid, a pattern of a cured-resin obtained by curing the photocurable composition is formed on a substrate. The photo-nanoimprint lithography does not need a heating and cooling step, and accordingly, resin molding can be performed at high speed at a constant temperature, such as room temperature.
As an example of the method to form a pattern of a cured-resin on a substrate by using a mold, there has been known a method of positioning a mold and a substrate with a gap held between the mold and the substrate; substantially filling the gap with a low viscosity photocurable composition having a viscosity measured at 25° C. of less than 30 millipascal seconds (30 mPa·s); and curing the photocurable composition by light irradiation (for example, refer to PTL 1).
In the method for producing a substrate with a fine projection-and-recess pattern by photo-nanoimprint lithography, as a process to apply a photocurable composition on a substrate, there has been commonly performed: a pattern formation process (for example, refer to PTL 2) including the steps of applying a photocurable composition for photo-nanoimprinting onto a substrate by a spin-coating process to form a pattern formation layer, pressing a mold into contact with a surface of the pattern formation layer, and irradiating the pattern formation layer with light; or a pattern formation process (for example, refer to PTL 3) including the steps of applying a photocurable composition for photo-nanoimprinting onto a substrate or a mold having a fine pattern by an ink-jet printing process, and irradiating the photocurable composition for photo-nanoimprinting with light, with the photocurable composition being sandwiched between the mold and the substrate.